SRAM AXS (MTB) Derailleur / Cassette Contact?

Anyone run into this before? Just switched to a smaller chainring, dropped two links out of my chain, and now on my two largest rings of a 10-52 cassette, there’s overlap of the rear deraillur jockey wheel and the cassette ring when I’m shifting to the larger ring, which is causing some contact and grinding when I shift.

Chain length is to SRAM spec, but looks like there’s room for me to take another two links out which appears would lessen or eliminate the overlap.

EDIT: Also made sure my derailleur hanger was straight, and set chain gap per SRAM specs before getting to this point.

Have you checked the B-tension lately?

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Yes, just checked derailleur hanger and set chain gap to spec.

Is the spec using that white plastic guide/tool that comes with it?

I have no other guesses sorry. It very much looks like B-Tension to me. Assuming the chain is routed correctly through the derailleur etc :man_shrugging:

Yes, that’s the tool used to set it. According to this process, I’m dead on.

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I’m out of ideas sorry

Something is wrong on your setup, look where the upper pulley is in relationship to largest cog and compare it to your setup. If you’ve set the b-gap using that tool, then it’s not done right. Has the derailleur been taken off? are you certain the stop is in the right spot on the hanger?

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The b-washer needs to be in contact with the face of the hanger. This video shows it.

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this shows it better.

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Yep sounds like derailleur not installed to new hanger properly after changing the hanger over.

There’s a little ledge on the b-screw washer, check that hasn’t sheared off too. Mine has broke once before.

Also for AXS, make sure to set the b-gap at say for proper smooth shifting.

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@Cory.Rood @Jbhkhc - Unless I’m missing something, that’s not it. I’ve literally had the damn thing off 3 times checking exactly that. (And that second video is the one I’m using). Basically get it almost snug, and then rotate downwards so the washer rests against the flat on the derailleur hanger.

Can you show it with the b-gap tool installed?

Not until midweek, but I will if I don’t have it figured out. Done for tonight and it’ll be Wednesday before I get to retry that though.

For what it’s worth, I’ve done that step Twice, so I don’t think that’s it. And, I swear that damn brittle plastic tool cracks every time I use one so now I need to hold it in place or buy another.

are we working on a HT or FS? You say you went to a smaller chainring, and you resized the chain? do you have the other b-gap tool?

FS. Set with suspension at full compression. I’ve only used the white tool, never any other version.

and you followed the chain sizing for FS, not HT, correct?

Correct. But basically, chain was slack before shortening when in the smallest gear. Removed two links, re checked and right at spec.

here are the instructions for doing it without the tool.

  1. Shift the chain onto the second largest rear cog. For full suspension bicycles, measure the chain gap while the bicycle is in the sag position.

  2. Rotate the B-Adjust screw until the gap between the upper pulley and the tallest teeth of the largest cog is 3 mm.

obviously from your picture you’re not there.

Just installed this on my FS MTB a few weeks ago.

Are setting the “B” gap when the suspension is at sag? The chain length gats set at full compression and the “B” gap at sag.


You know what, I bet you just caught the issue and I haven’t re-checked this. I’m going to wager that it wasn’t actually correctly at sag because I was going back and forth so much trying to figure it out, and that’s throwing it off. Basically - doing this on my own so I’ve always had to measure and then deflate the shock some to the appropriate compression/sag and I’m now thinking I didn’t do that right this time.

Before we go all around on this anymore, I need to re-check that.